What is CVE-2021-34433?

CVE-2021-34433 is a high-severity vulnerability in Eclipse Californium, classified under Key Exchange without Entity Authentication. CVSS score: 7.5/10. Published 2021-08-20.

How severe is CVE-2021-34433?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Eclipse Californium

CVE-2021-34433

In Eclipse Californium version 2.0.0 to 2.6.4 and 3.0.0-M1 to 3.0.0-M3, the certificate based (x509 and RPK) DTLS handshakes accidentally succeeds without verifying the server side's signature on the client side, if that signature is not included in the server's ServerKeyExchange.

Published 2021-08-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (25.0th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Eclipse Californium — versions 3.0.0
The Eclipse Foundation Californium — versions 2.0.0, unspecified, 3.0.0-M1

Weakness classification (CWE)

References

bugs.eclipse.org/bugs/show_bug.cgi (Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2021-34433?: CVE-2021-34433 is a high-severity vulnerability in Eclipse Californium, classified under Key Exchange without Entity Authentication. CVSS score: 7.5/10. Published 2021-08-20.
How severe is CVE-2021-34433?: High severity. CVSS v3 base score is 7.5 out of 10.